Joshua Boyle — formerly married to Omar Khadr’s sister — and his pregnant wife have vanished in Afghanistan. Their parents are pleading for their safety.

Joshua Boyle, seen in 2009, has been missing in Afghanistan since October with his pregnant American wife, Caitlan Coleman. Boyle has described himself as a research fanatic. He was briefly married to Zaynab Khadr several years ago and served as a "spokesperson" for the Khadr family.

It is now feared the young couple, who did not come home by early December as planned, may have been kidnapped. However, no demands for ransom have been made.

Worried about Coleman’s health, their parents have broken their silence to issue public pleas.

“We are all anxiously awaiting some word on their well-being or whereabouts and are constantly praying for their safe return,” Boyle’s parents Linda and Patrick wrote to the Star in an email Monday night.

“We have not been contacted by anyone claiming to have them or seen them since early October, when there were local reports of a kidnapping in the region.”

Their marriage lasted a year, ending in early 2010. A year later, Boyle married Coleman.

“Unaware of the difficult residence and work issues upon a Canadian and American marrying, they planned a series of lengthy travels for 2 years before settling down to family life,” Boyle’s parents said.

“In 2011, they spent 4 months travelling throughout all the countries of Central America, returning for Thanksgiving. They enjoyed staying in hostels and tents, connecting as much as possible with local people and helping out as opportunities arose.”

Boyle kept in touch with a Star reporter during those years, writing periodically about his travels. In September 2011, he emailed from Honduras that he was doing volunteer work.

His last email to the Star was sent in March, when he said he was set to travel again soon.

Boyle, a graduate of the University of Waterloo, took a keen interest in national security and human rights issues following the Sept. 11, 2001 attacks; it was through his advocacy that he met Khadr in 2008.

They were married just after New Year’s in 2009 — an unlikely union that was kept out of the public eye until a mysterious break-in at the home of Boyle’s parents and subsequent speculation it could somehow be linked to their recent wedding. There were no arrests in the break-in.

A 2009 photo of the couple shows Boyle with a beard and long hair adorned with dandelions holding Safia, Khadr’s daughter from a previous marriage. Khadr has a cluster of dandelions tucked into her niqab.

After their divorce Boyle moved to New Brunswick and began travelling.

Boyle’s parents said he left with Coleman in July for a six-month trip to Russia and Central Asia.

“They were to have returned in early December. We weren’t aware of Caity’s pregnancy when they left,” the Boyles said in their email. “Afghanistan was not part of their original travel plan.”

They had spoken of planning a similarly long trip to Australia in 2013.

“We’re trying very desperately to find out information about our daughter, and we want it to get out there to those that might be able to help us find her and get her home,” Coleman’s mother Lyn told the Star by phone from their Pennsylvania home Monday. “We’re trying just to get the information out that she is missing, she is pregnant, she has medical problems.

“We need to get our daughter and her husband and child, our grandchild, home.”

James Coleman earlier told The Associated Press that they last heard from Josh on Oct. 8. He said he was in an Internet café in what he described as an “unsafe” part of Afghanistan. The last withdrawals from their bank account were made Oct. 8 and 9 in Kabul, the Afghan capital.

“We thought they were very naïve in where they were going but —” said Lyn Coleman, before choking up.

The Colemans were not sure how the young couple got into Afghanistan or what they intended to do there, though they described them as “tourists.”

According to media reports in October, two foreigners thought to be Canadian and American went missing while travelling to Kabul from Ghazni in an area notorious for Taliban attacks and checkpoints. Afghan police suspected the Taliban in the disappearance and said they had information that the abductees were to be taken to Pakistan. The trail later ran cold.

A tribal elder in the region said the road on which the missing pair was reportedly travelling was so dangerous that even locals wouldn’t use it. The two were never identified by name

When The Associated Press contacted Taliban spokesman Zabihullah Mujahid two months ago about the missing couple, Mujahid said the group had investigated and found no Taliban members were involved.

Canadian and American officials said they were aware of the reports of a missing couple din Afghanistan.